Extraction And Genotypic Varietion Of Antioxidant Functional Components From Sweet Potato Vines

Sweetpotato is an important agricultrual and economic crop in China.Recently,the development and utilization of natural products in sweetpotato vines have been noticed by more and more scholars.In this paper,the extraction process of flavonoids,polyphenols and chlorogenic acid was optimized by double aqueous phase extraction and separation system.Meanwhile,20 different types of sweetpotato varieties were selected as experimental materials to explore the differences of antioxidant functional components and the antioxidant functions of different extraction sites.Furthermore,the flavonoid genes of three varieties was analyzed by RT-PCR analysis.The main innovative results were as follows:(1)Ultrasound-assisted extraction of flavonoids from di-potassium hydrogen phosphate aqueous two-phase extraction system: potassium dihydrogen phosphate 30%,ethanol 30.65%.0.45 g sample was needed every 10 g extraction system.The optimal extraction conditions for polyphenols were: 2.51 g of dipotassium hydrogen phosphate,30.5% of ethanol,and an ultrasonic time of 36.85 min.The optimal extraction process of chlorogenic acid was: dipotassium hydrogen phosphate 3.18 g,ethanol 33.63%,ultrasonic time 49.79 min.(2)The flavonoid content reached its peak in ornamental cultivar Taiwan Red,and its lowest content was in Xushu 27.The content of polyphenols was the highest in Xushu 25,and in tobacco purple potato was the lowest.Xushu 25 had the highest chlorogenic acid content,Qinchun potato No.4 had the lowest in Zishu No.3;the highest content of vitamin C was Yanzishu No.4,and Qishu No.2 was the last one,The content of anthocyanin varied significantly among different varieties.The highest content of anthocyanin was Taiwan red,followed by the purple sweetpotato3,and the lowest was in Xushu 25.Correlation analysis results showed that there was a significant positive correlation between polyphenols and chlorogenic acid at 0.01 level,and polyphenols were significantly negatively correlated with anthocyanins.The content of flavonoids was positively correlated with vitamin C and polyphenols.The order of antioxidant functional substances in stem and petiole was: leaf> petiole> stem.(3)The expression level of Ib PAP1 and Iban1 genes in Taiwan red,Yanzishu-4 and Qinshu 5 were significantly different.The expression of purple sweet potato leaves in Taiwan red was significantly higher(p<0.05)than that of Zhezishan.4 purple potato leaf and green leaf variety Qinshu 5,and the content of anthocyanin in sweet potato was significantly(p<0.05)correlated with leaf color.The content of phthalocyanine was generally higher than that of green leaf cultivars;the content of flavonoids in sweet potato leaves was coincidence with RT-PCR results in Taiwan Red>Xiezishu 4>Qinshu 5.